Question

For each pair of substances, anticipate which one has a higher boiling point.
HF has a .... than HCl .
CCl₄(l) has a .... than CH₃Cl(g) .
CH₃OCH₃ has a .... than CH₃CH₂CH₃ .
CH₃OCH₃ has a .... than CH₃NHCH₃ .
H₂S has a .... than H₂Se

Answer 1

CHCl3 BP = 61, could be very slightly polar theoretically.
both tetrahedral structure,
molar mass (dispersion forces) probably greatest factor in difference.

CH3OCH3 BP = -24, 1.3D (dipole moment), bent geometry
CH3CH2CH3 = -42, nonpolar
molar mass very close.
Polarity probably accounts for increased intermolecular attractions and increased BP

CH3CH2OH BP = 78, 1.7D,
CH3OCH3 BP = -24, 1.3D
O at end of chain "less hidden" than O in middle of chain.

HF BP = 19, 1.9D
HCl BP = -85, 1D
greater electronegativity of F compared to Cl makes HF bond more polar.

CH4 BP = -162, nonpolar
SiH4 BP = -112, nonpolar
greater molar mass = ....

Answer 2

CHCl3 BP = 61, could be very slightly polar theoretically. both tetrahedral structure, molar mass (dispersion forces) probably